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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society for Noise and Vibration Engineering
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Journal DOI :
The Korean Society for Noise and Vibration Engineering
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Volume & Issues
Volume 14, Issue 12 - Dec 2004
Volume 14, Issue 11 - Nov 2004
Volume 14, Issue 10 - Oct 2004
Volume 14, Issue 8 - Aug 2004
Volume 14, Issue 7 - Jul 2004
Volume 14, Issue 6 - Jun 2004
Volume 14, Issue 5 - May 2004
Volume 14, Issue 4 - Apr 2004
Volume 14, Issue 9 - Mar 2004
Volume 14, Issue 3 - Mar 2004
Volume 14, Issue 2 - Feb 2004
Volume 14, Issue 1 - Jan 2004
Selecting the target year
Development of Speed Increaser for High Speed Machine Pump which Considered the Noise/Vibration
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 363~369
DOI : 10.5050/KSNVN.2004.14.5.363
Vibration/noise analysis as well as strength of gear teeth, roller bearing life. joural bearing design are considered in order to develop the high-speed machine centrifugal pump which had a speed increaser. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmitted errors of the gearing are considered. shows that. at the operating speed. there are not the critical speed. A high-speed machine centrifugal pump was made in order to evaluate developed speed increaser. Also, strict API standard were introduced for reliability evaluation of developed speed increaser, and performance evaluation were carried out. The result that evaluation items about bearing vibration, shaft vibration, noise, and lubrication temperature were selected, and were tested. a high-speed machine centrifugal pump were able to know what were satisfied with API standard all.
Optimum Welding Position between Shell and Cylinder based on SEA
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 370~376
DOI : 10.5050/KSNVN.2004.14.5.370
The overall aim of this paper is to determine coupling loss factor of welding point between shell and cylinder using loss factor and structural loss factor. For this purpose, two kinds of loss factor were adopted. One is loss factor of each sub structure, another is structural loss factor based on the complex welded or assembled structure. Using these two parameters, it ispossible to derive the coupling loss factor which represent characteristic condition of SEA theory. Coupling loss factor of conjunction in complex structure was expressed as power balance equation. The derived equation for a coupling loss factor has been simplified on the assumption of one way (uni-directional) power flow between multi-sub structures. Using these conditions, it is possible to find the equation of coupling loss factor expressed as above two loss factors. To check the effectiveness of above equation, this paper used two-stage application. The first approach was application between simple cylinder and shell. The next was adopted rotary compressor. Rotary compressor has three main conjunctions between shell and internal vibration part. This equation was applied to find out the optimum welding point with respect to reduce the noise propagation. It shows the effective tool to evaluate the coupling loss factor in complex structure
Impulse Response Analysis of an Amplitude Proportional Friction Damper System
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 377~384
DOI : 10.5050/KSNVN.2004.14.5.377
An Amplitude Proportional Friction Damper (APFD), in which the friction force is proportional to the system displacement, has been introduced and mathematically modeled. To understand the damping characteristics of APFD, analytical solutions for the impulse response has been derivedand compared to the viscous damper. It is found that APFD system has very similar damping characteristics to viscous damper even though it is a friction damper. APFD may be used as a cost-effective substitution for the viscous damper and could also be used to improve the simple friction or Coulomb dampersince APFD works with no stick-slip and always returns to original position when external disturbance is disappeared.
Track-following Control of an Optical Pick-up Actuator Using PZT
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 385~393
DOI : 10.5050/KSNVN.2004.14.5.385
This paper proposes a swing-arm type dual-stage actuator, which consists of a PZT actuator for fine motion and a VCM(voice coil motor) for coarse motion, for an SFF ODD(small form factor optical disk drive), in order to achieve fast access speed and precise track-following control. Over the past few decades there have been a lot of researches related to the VCM and dual-stage actuator. In this paper, we focus our attention on the design and control of the PZT actuator. Due to the dual cantilever structure. the PZT actuator can generate precise translational tracking motion at its tip to which an optical pickup is attached. and the effect of hysteric behavior of the PZT element is reduced. The dynamic model of the PZT actuator is derived by using the Hamilton`s principle, and verified by comparing it with the experimental frequency response. The sliding mode control is designed in order to be robust against modeling uncertainties. Simulations and experimental results confirm the effectiveness of the suggested control scheme.
Impact Responses of Two Colliding Bodies Considering Sensor Dynamics
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 394~401
DOI : 10.5050/KSNVN.2004.14.5.394
This paper presents a study on the analysis of impact responses taking into account sensor dynamics. The contact force between impacting bodies is modelled by using Hertz force-displacement law and linear damping function. Since the real impact force and acceleration at the contact surface of two colliding bodies are measured indirectly by the sensors, the measured outputs can be a little different from the real impact responses. Therefore, in this study, the importance of consideration of sensor dynamics in the impact problems of two colliding bodies is emphasized. In order to verify the appropriateness of the proposed contact force model, the drop type impact test using two kinds of sensors is carried out. Through the numerical analysis and experiment, the effect of sensor dynamics and characteristics on the contact force model is investigated.
Flow-induced Vibration Analysis of Bridge Girder Section
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 402~409
DOI : 10.5050/KSNVN.2004.14.5.402
Numerical analysis of static and dynamic wind effects on civil engineering structures was performed. Long-span suspension bridges are flexible structures that are highly sensitive to the action of the wind. Aerodynamic effect often becomes a governing factor in the design process of bridges and aeroelastic stability boundary becomes a prime criterion which should be confirmed during the structural design stage of bridges because the long-span suspension bridges are prone to the aerodynamic instabilities caused by wind. If the wind velocity exceeds the critical velocity that the bridge can withstand, then the bridge fails due to the phenomenon of flutter. Buffeting caused by turbulence results in structural fatigue, which could lead to the failure of a bridge. Navier-Stokes equations are used for the aeroelastic analysis of bridge girder section. The aeroelastic simulation is carried out to study the aeroelastic stability of bridges using both Computational Fluid Dynamic (CFD) and Computational Structural Dynamic (CSD) schemes.
Evaluation of Blades Vibration Reliabilities of KGT-74 Small Gas Turbine
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 410~415
DOI : 10.5050/KSNVN.2004.14.5.410
To ensure a safe operation of the prototype KGT-74 kW small gas turbine, vibrational reliabilities of the compressor 1st, 2nd, and 3rd stages and turbine blades have been estimated and reviewed. FE analyses have been carried out to obtain the natural vibration characteristics of the blades, and impact modal testings have been performed on every each one of the blades to measure their 1st natural frequencies. Then, the Campbell diagram analyses have been carried out to judge the safety of the blades from resonant failures up to 6k harmonics. Results show that the compressor 1st stage blade is exposed to a potential resonant failure with 3k harmonic around a rated speed of 30,000 rpm but that the other compressor 2nd and 3rd stages and turbine blades are safe from resonant failures. Finally, 27,900 rpm is selected as the safe operation limit for the KGT-74 ㎾ gas turbine relative to the blade vibrations.
System Identification of a Three-story Test Structure based on Finite Element Model
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 416~423
DOI : 10.5050/KSNVN.2004.14.5.416
In this paper, an experimental verification of system identification technique for constructing finite element model is conducted for a three-story test structure equipped with an active mass driver (AMD). Twenty Gaussian white noises were used as the input for AMD, and the corresponding accelerations of each floor are measured. Then, the complex frequency response function (FRF) for the input, the force induced by the AMD, was obtained and subsequently, the Markov parameters and system matrices were estimated. The magnitudes as well as phase of experimentally obtained FRFs match well with those of analytically obtained FRFs.
A Transient Response Analysis in the State-space Applying the Average Velocity Concept
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 424~431
DOI : 10.5050/KSNVN.2004.14.5.424
An implicit direct-time integration method for obtaining transient responses of general dynamic systems is described. The conventional Newmark method cannot be directly applied to state-space first-order differential equations, which contain no explicit acceleration terms. The method proposed here is the state-space Newmark method that incorporates the average velocity concept, and can be applied to an analysis of general dynamic systems that are expressed by state-space first-order differential equations. It is also readily coded into a program. Stability and accuracy analyses indicate that the method is numerically unconditionally stable like the conventional Newmark method, and has a period error of 2nd-order accuracy for small damping and 4th-order for large damping and an amplitude error of 2nd-order, regardless of damping. In addition, its utility and validity are confirmed by two application examples. The results suggest that the proposed state-space Newmark method based on average velocity be generally applied to the analysis of transient responses of general dynamic systems with a high degree of reliability with respect to stability and accuracy.
Acoustic Levitation and Rotation Produced by Ultrasonic Flexural Vibration
Loh, Byoung-Gook ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 432~438
DOI : 10.5050/KSNVN.2004.14.5.432
Acoustic levitation induced by ultrasonic flexural vibration at 28.4 KHz with a vibration amplitude of 10 micrometers is presented. Levitation of multiple objects along the length of the beam in a gap of 8.3 mm which is the half of acoustic wavelength is experimentally demonstrated. Analytical analysis predicts that levitated objects for the gap of half-the wavelength converges to the center of the gap, which is experimentally verified. It is observed that levitated objects with well-balanced mass distribution are set into rotation due to acoustic streaming. For cylinder-shaped Styrofoam with a diameter of 1.8 mm and a length of 3 mm, measured rotational velocity is 2400 revolution per minute. Applications of standing wave field levitation (SWFL) include manipulation of biological cells and blood constituents in biotechnology, and fine powder in material engineering.
Sliding Mode Control of an Active Magnetic Bearing System
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 5, 2004, Pages 439~448
DOI : 10.5050/KSNVN.2004.14.5.439
Magnetic bearing is an attractive device in precision engineering field because of its non-contacting nature and controllability of its dynamic characteristics. This paper provides a method of designing a sliding mode control for an active magnetic hearing(AMB) system which is used to support the elevation axis of a target tracking sight instead of mechanical bearings to eliminate the effect of mechanical friction. In such system, the axis should be levitated and supported within a predetermined air gap while AMB is excited by base motion. Experimental results showed that the sliding mode control is effective in disturbance rejection than conventional PID-control without any additive measurements.